My question is to correct the faulty parallelism.How can we do that.

"The streets were not only too steep but also were too narrow for anything other than pedestrian traffic."

The structure is parallel. Perhaps the second were isn't needed. Please check back here because another English teacher may have a better answer.

Ms. Sue is right. Remove the second were.

Here's a good section explaining parallelism:
http://grammar.ccc.commnet.edu/grammar/parallelism.htm

=)

To correct the faulty parallelism in the sentence, you can remove the second "were" so that it reads: "The streets were not only too steep but also too narrow for anything other than pedestrian traffic."

In parallel construction, similar grammatical structures should be used to express related ideas. In this case, "too steep" and "too narrow" are the two conditions being conveyed, so they should be expressed using the same grammatical structure.

If you encounter similar situations where you need to correct faulty parallelism, you can follow these steps:

1. Identify the elements in the sentence that need to be parallel.
2. Ensure that these elements are expressed using the same grammatical structure, such as verb forms, adjective patterns, or noun phrases.
3. Make any necessary adjustments to ensure consistency and clarity in the sentence.

For further guidance on parallelism, you can refer to the link provided: http://grammar.ccc.commnet.edu/grammar/parallelism.htm